Electrically-driven reciprocating tool for riveting, calking, stonecutting, etc.



June 112, 1923. 1.458439 J. J. ROBERTS ELECTRICALLY DRIVEN RECIPROCATING TOOL FOR RIVETING, CAULKING,

STONECUTTING, ETC 7 Filed Oct. 25 1920 2 Sheets-Sheet 1 June 12, 1923.

J. J. ROBERTS ELECTHICALLY DRIVEN RECIPROCATING TOOL FOR RIVETING, CAULKING,

STONECUTTING, ETC Filed Oct 25 1920 2 Sheets-Sheet 2 Patented June 12, 1923.

warren stares JOHN J. RDBERTS, OF LOUISVILLE, iif'dil f'flil asses rarear d, CALKING, STONE- Applicatlon filed October 25, 1920. Serial No. 419,489

To all whom it 11mg concern-.- Be it known that 1, JOHN J. ROBERTS, a 'itizen of the United States, residing at Louisville, in the county of Jefferson and State of Kentucky, have invented new and useful Improvements in Electrically-Driven Reciprocating Tools for Riveting, Calkmg, btonecutting, Etc, wherein new and useful designs in the construction of electrlcallyniven hammers and other reciprocating inrplements have been devised and new and useful means for operating and controlling said reciprocating devices have been invented.

The objects of my invention are,'-(l) to designand construct an electrically driven hammer operative on either the direct or the alternating current with greater convenience and less expense than is now ossible with an air-driven hammer of equa working power. (2) to devise a novel hammer head provided with guide rails and a tappet lu forth in straight lines; (3) to provide suitable meaps adapted to engagesaid guide rails and thus to hold'the hammer head in its operative position; (4) to design unique and practical motor-driven means to be placed adjacent said hammer head and adapted in normal operation to engage said tappet lug intermittently so as to force the hammer head upward its predetermined distance and then to release the lu again; (5)

to provide a spring and auxi iary means adapted to be set in the upward movement of said hammer head so as to force the head downward again in a free normal stroke, as

said tappet lug is released, which completes the reciprocating movement of said hammer head; (6) to construct for an electric riveting hammer a nozzle and a rivet set adapted to fit therein and receive the blows of the hammer head, also auxiliary means for securely retaining the rivet set with a certainslight longitudinal movement in the nozzle in which spring-pressed means always holds the set in its operative position; (7 to design and develop for an electric .tool a manually operative switch adapted to close the electric circuit in said electric tool when? ever pressure enough is exerted upon the handle of tool to push it normally to its work; (8) to provide suitable means for dissipating the internally generated heatunits and adapted in normal operation to be, driven a predetermined distance back and.

as rapidly as they are enerated in normal operation, so that the e ectric hammer may operate continuously at a desirable temperature; and (9) to design and construct for an electric hammer an operative mechanism comprising a hammer head and its actuating and coacting parts all adapted to lift the hammer head and to strike the blows with great rapidity and with a minimum of external vibration to the operator, the haminer head with its co-acting parts being adapted to deliver its stroke while entirely free from mechanical connection with the electrically driven parts thereof.

All these objects are attained in the present invention, and the electrically driven reciprocating tool illustrated in the accompanying drawings which form a part of this specification, is a practicable apparatus embodying the aforesaid novel means and other new and useful details of construction, arrangement and combination of parts, all of which together'with their functions will be described in detail with reference to said drawings, and will be definitely pointed out in the claims that follow the description.

In said drawings, Fig. 1 is a longitudinal section of my electric hammer and easing along the axis, with the handle, one tie rod, a part of the tail cap, one guide post and the moving parts of the hammer showing in elevation, the other guide post and tie rod having been removed by the section. Fig.2 is a detail of the reciprocating mechanism and frame thereof showing a fragment of the casing in section and the other parts of the mechanism and frame, and also fragments of the nozzle and the rivet set, in elevation.

This invention has been developed for general use where an eflicient reciprocating power tool large or small is desirable, and may be made in differently shaped casings for different uses without departing from thgvprinciple of the invention.

ith the general purpose and the special objects aforesaid in view, I will now describe 2 points out the field iron 3, the armature of the electric motor part of the hammer; and 4 indicates the hammer casing.

The automatic switch. As shown in Fig. 1, switch knife 27 is bin (1 at pintle 26" in pintle post 26, a art of t 0 base of which is used as a'bin ing post for circuit wire 26 as it comes through a hole in casing 4; and the switchknife 27 appears standing out of its clip 27, a part of the base of which is used as a binding 0st for circuit wire 27 from said clip 27 to field coil 27?; and the switch is open as the knife 27 stands out of the clip 27, having been pushed out of said clip 27 by means of the helical switch spring 30 under compre$ion in its insulating socket 29, the upper end of which is seen to be slotted to allow the movement, of the knife 27. On the upper edge of knife 27 .rides push pin 33- securely fixed in the insulating block 33, the

' inner part of which is made readily removable with a punch passed through the threaded hole in base 33 now closed with the threaded stopper 33.

Inside the upper end of easing 4, tool handle base 32 with its tubular extension 32 is slidably inserted and held in place by means of the annular cap 31 which'is fastened to casing 4 with screws 31; and ust below said tubular extension 32 inside casing 4 1s fixed the insulating disc 28, down through the central part of which is screwed 'the inner guide tubing 29 adapted to fit closely into the outer guide tubing 34 to cause the handle base 32 with its tubular extension 32 to slide in straight lines without rocking when the handle 32 is pushed downward to close the switch. Tube 34 is also slotted.

It can now be readily seen that when wires 25 and 26 are energizedand handle 32 is pushed downward hard enough to overcome switch spring 30, push pin 33' riding on the upper edge of switch knife 27 forces the switch knife into its clip 27*, thus closing the motor circuit, and the current running in on wire 26 would pass through bind ing post and knife post 26, knife 27', clip 27*, and its binding post, wire 27 coil 27", wire 27 and its post to commutator brush 5; thence through armature coils 3, brush 5, wire 25 and its post, field coil 25 and out along circuit wire 25, thus operating the motor so long as the slidable handle part is kept pressed downward hardenough to hold the knife switch closed. But when the handle is released, switch spring 30 forces upward knife 27 out of its clip 27, the circuit to the motor is opened and the motor stops. It is seen now that as the knife 27 is forced upward, it in turn forces upward the push pin 33 and it-sbase, arts 32 and 34 to the upper end of its sli e, as shown in Fig. 1 in which position a is held by spring 30 with the motor circuit open until the handle is pushed downward again to operate the motor. The characters 2, 2 indicate ventilation holes to the switch chamber. y

. The electric motor.

Next below the switch mechanism in has- .ing 4 is installed the tool motor, the field the casing 4 by means of the screws 23-2, Fig. 1, and the armature'3- being journaled at the upper end in the bushing 24 in plate 23 which is fixed in the casing 4 by means of screws-235 23; while at the lower end, the

armature is journaled in the bushing 6- fastened in gournal plate 6. The motor is ser1es woun with its commutator brushes set opposite each other, being bipolar and v iron 2, 2 and coils 25, 27 beingsecured to adapted to operate on either 'the D.- C. or I to the motor parts is effectually prevented by the deflection disc 3 fixed in the casing 1 between the motor and the centrifugal fan 3". -The lower end of the'shaft of armature 3 carries the piniongear 6 justbelow its bushing 6.

I The rciprocating mechanism. I

In the lower section of tool'casing 4 is On. the armature shaft,-

installed my reciprocating mechanismland its frame. -The head cap 16 and the tail cap 17 areparallel disc plates tied together rigidly with the two tie rods 22, 22 and with the two guide posts 21, 21, 'Fi 2. Both the tie rods 22, 22, and the gui e posts'21,

21, are screwed into head "cap 16 at right angles to the disc; then they pass through tai cap 17, being collared andsecured by means of nuts 2 22 and 21" and 21", Fig. 2. Within this rigid frame the reciprocating mechanism of'my electric hammer is mounted. The hammer head 20 is provided with a spindle 20v adapted to pass up through plate 16 and to hold in operative position the helical compression spring 20 which abuts plate 16 and hammer head 20.

Figs. 1 and 2. The hammer spring 20 is adapted to be set whenever the hammer head is pushed upward and to force the hammer head back downward again when the head is released from its upward pressure. Hanr mer head 20 carries on its inner side arigid tappet lug 20 on which is movably fixed a thick sleeve 20 adapted to rotate easily on said lug. The hammer head20 is also pro;

vided on either side with parallelguide rails 20, 20, rigidly fastened to said head by means of rivets 20, 20, etc., and ddapted to fit slidably into the longitudinal slots 21, 21 in the sides of the guide posts 21, 21, adjacent the hammer head, Figs. 1 and 2. These guide rails 20?, 20 and slots 21*, 21 in the rigid guide posts 21, 21 are adapted to cause the hammer head 20 with its guide rails 20 20 to move only strai ht lines and inthe same plane as it is force up and down in normal operation over its predetermined operative gap.

Mounted in the reciprocating mechanism frame is a rotatable shaft 9, the upper end of which journaledv in head cap 16 carries just above said head cap a pinion gear 11 adapted when rotated to rotate said shaft.

The lower end of said shaft 9 is journaled in the ball bearing box 10 fixed in tail cap 17, Fig. 1. ()n shaft 9 near its lower end is mounted a cylindrical cup 8 open at the top while its bottom is centrally bored and provided with hubs projecting inside and outside through which the hub pins 8, 8* are driven to fasten said cup 8 rigidly to shaft 9. The sides of said cup around the upper part have been cut to form a helical incline 14 leading from near the bottom of the cup g-'adually up to the top to a peak 14 having on its opposite side a sharp declivity 14c extending downward to the lowest part of the helical incline 14. Now cylindrical cup '8 when driven by shaft 9, is adapted to rotate with its helical incline 14 always passing under tappet In 20 with its rotatable sleeve 20; and this rotating movement of the helical incline 14 on cup 8 in normal operation causes sleeve 20 on tappet lug 20 to roll up over helical incline 14 to peak 14 as seen in Fig. 1, when, as the peak 14* passes, lug 20, 20 under pressure of spring 20", jumps down the declivity 148 to the lowest part of. the incline 14, as seen in Fig. 2; and then starts up the helical incline 14c again. Thus hammer head 20, by means of its tappet lug 20, 20 actuated by the rotating cylindrical cup 8 with its helical incline 1 is lifted up its predetermined distance; and by means of the compression spring 20 said hammer head, when released by the passing of peak 14", is forced downward and delivers its blow in normal -internal explosions of compressed air or steam in the air hammer.

In the cylindrical cup 8, on the limb where the sides of the cup are low-cut there is not so much weight as on the opposite limb where the sides are high-cut; consequently, in the rotation of cup 8, the centrifugal force of these said opposite limbs will not be e ual; moreover, as the tappet lug 20", 20 o the hammer head 20 is not being raised throughout the whole cycle of rotation of said cup 8 there is intermittent work being done by said rotating cup. Therefore, to compensate this intermittent work and the une ual centrifugal force from the rotation of t e cups limbs of unequal Wei ht, I have fastened near the upper end of s aft- 9 just under head cap 16 a stabilizer consisting of an inverted cylindrical cup 7 of nearly the same weight and shape as cup 8, the bottom of cup 7 emg centrally bored and provided with internal and external hub projectionsv through which the pins 7, 7 hold said cup securely to shaft 9. Cup 7 is mounted on shaft 9, having been cut and adjusted and thus adapted to compensate the unequal centrifugal forces of the heavy and the light limbs and also the intermittent work of cup 8 in its cycle of'rotation innormal operation.

Between plate 6 and headcap 16 is installed the compound gearing 12, 12, journaled in said plates, the upper gear 12being adapted to mesh with pinion 6 on the lower end of-the shaft of armature 3, while the lower gear 12 is adapted to mesh with pinion 11 on the upper end of shaft 9; all

of which spur gears together; as seen in Fig. 1, constitute the gear train adapted to drive shaft 9 and its attachments 7 and 8 to raise said hammer head intermittently a predetermined distance against the pressure of the main spring 20", when the hammer motor is operating. 1

The nozzle and the Meet-set.

part 18 of the nozzle directly in line with the operative movement of hammer head 20, said fixed part 18 of the nozzle being provided with a central boring reaching through the base 18- and on directly through the adjacent part of the tail cap 17 under the face of hammer head20, Figs. 1 and 2. Said boring is adapted to receive any tool bit such as the rivet set 19, 19 appearing in Fig. 1 partly in section and partly in elevation, whose shank 19, a reduced portion, is ada ted to reach up through said boring so t at its face 19 can receive the blows of hammer head 20 in its normal operation. Fixed part 18 of the nozzle is also provided with a short counterboring concentric with the central boring aforesaid; and rigidly pinned to shank 19 is collar 19 which is adapted tosettle against' p inn t of-its working stroke with itsface 19 down" in the same plane with the up er iny electric hammer.

.19 of said sleeve is .counterbore of the fixed part 18,

the fixed part 18" and the the "bottom shoulder o the counterbore vallowin the shank 19 to. stand a predeter mine distance above thermner surface of- 17 tofreceive the blows of hammer,

tail cap head 20.- Said counterbore of the fixed ,part 18, is provided with .threads;.and 'rivet set. 19, l9 is provided with aheavy,

sleeve 18 as seen in Fig. 1 partly in elevation and partly in section. The inner en provided with threads and adapted to be screwed into the threadeg sleeve making a closejoint and'even sure face with the fixed part 18 so that both removable art, sleeve 18, together constituteth'e nozz e of And in the outer end of sleeve 18 is a shallow counterbore adapted to' take in apart of the rivet set head 19 for a predetermined distance, which I 19, adapted to be held securely in the nozzle, should have sufficient longitudinal movement therein to enable it to complete its normal. w rk stroke under the impulse of the ham er blow. Such longitudinal movement is provided for in the following manner: Within the counterbore ofthe fixed part 18", between the collar 19 and the threaded part 19 of the sleeve 18 is a clear space along shank 19*, which is pro- 'vided with a helical compression spring 19 partiall set, one end of which abuts collar 19. whi t ,the other end abuts the threaded portionL'19l of sleeve 18. The process of screwing the sleeve 18 into the fixed part t e nozzle compresses spring 19 hard enough to hold shank 19? up in its normal position to receive the hammer strokes; and

the further compression of the said spring 19,- under the impulse .of the normal blow of hammer head 20, allows an outward working: stroke of rivet set 19, 19" independent of the body of the hammer 1, which is one of-the objects of my invention. And the counterbore in the outer end of sleeve 18 adapted to receive the head 19 of said rivet set under the force of spring 19, allows a predetermined amount of longitudinal movement of head 19 without the exposure of the inner shoulder of the head beyond the end of sleeve 18, WhlCh would endanger thefingers of the operator in making a hand hold on the nozzle. A

hammer head 20 In'Fig. 1 may be seen 1 with its lug :20,

at its maximum height,

"20 onthe peak 14 about to jump down the declivity 14" "to a place justfl above I the lowest part 15 of the helical incline 14, in which lowest position said lug may be. seen in Fig. 2, while hammer head 20 rests in its lowest position with its, face in contact with the upper surface of tail cap 17,.hav-

in normal operation. 7

ing forced the shank 19 downward to the surface of tail-'cap 17 for it is desira le that the brunt of the hammer head blows in normal 0 eration should fall primarily upon. shank ace 19, while itis in its upper position as it appears in Fig. 1; and when the shank is driven downward to the limit d. of its working stroke, the residual force of the hammer head should. fall u on tail 20?, 20 comes own in contact wlth the part 15 of the helical incline 14.

Having thus described the features of my invention, the operation, construction, arrangement and combination of 1ts parts,

what I claim in my lnvention as new and.

useful and what I desire to have outlined and specified in Letters Patent, I have here-- in below set forth specifically in the following claims.-

Claims.

tool provided with a handle, forriveting, calkin'g, stone-cutting, etc., a motor driven by electro-magnetism, an insulated electric circuit to said motor, a manually operative switch in sald circult adapted to be closed by pressure upon the handle of said tool and to beopened automatically by the release of said pressure, combined with a reciprocating member or hammer head, a rotatable cylindrical cup and its rotating shaft adapted to lift said hammer head intermittently a predetermined distance, a

spring adapted to force said hammer head down again, a stabilizer fixed to said shaft 1. In an electrically driven reciprocating I to compensate the intermittent work of said I cylindrical cup, a gear train adapted to drive said shaft from said motor, and a nozzle provided; with a long-shanked tool bit slidably fastened therein and adapted to receive the blows of said hammer head 2.- In an electrically driven riveting hammer, a rigid casing provided with-a'handlc on its-upper end and a tail cap on its'lower end, on said tail cap-a nozz e adapted to hold the shank of a toolbit slidably fastened therein, 'a compression spring in said 'nozzle adapted to hold said shank in its operative position, a hammer head in said casing adapted to be actuated alternately back and forth in straight lines and to strike hard'blows upon the end of said shank, a

spindle, in the upper end of said hammer head, a compresslon s ring on said spindle adapted to be set wil i the upward movement of the hammerhead and to force the hammerhead down again to strike its blow upon said shank in normal operation, parallel guide posts fixednear said hammer head on either side, longitudinal slots in the adjacent sides of said posts, longitudinally dis osed guide rails riveted to said head an adapted to fit slidably into said longitudinal slots and to cause said hammer head to move only in straight lines in normal operation, a rigid ta pet lug on the side of said hammer hea adapted. to be used in lifting said head, a sleeve rotatably fixed on said lu in combination with a rotatable cylindrica cup provided with a helical incline adapted to rotate under said lug so'as to lift said hammer head its predetermined distance intermittently and to release it again in normal operation, a rotatin shaft provided with end-thrust ball bearings to carry said cylindrical cup, a stabilizer on said shaft, an electric motor provided with a centrifu al fan to drive said shaft and keep said ammer at a desirable temperature in operation, a circuit to energize said motor and a switch to open and close said M circuit by means of the tool handle at the will of the operator, substantially as described.

3. In an electrically driven hammer provided with-rigid frame, an electric motor therein with its ener izing circuit, an automatic switch in sai circuit, a handle for said hammer provided with a base slidably fastened in one end of said frame, a guide tube concentricall fixed in said base and extending inward y, rigid means for slidably engaging said guide tube to minimize the rocking of said base and handle in normal operation, means for closing said switch with the inward movement of said base in and (o-acting mechanlsm operative by said motor and adapted to drive said hammer head in one direction, a spring adapted to absorb the momentum of said hammer head as it makes its initial movement and also adapted to drive said hammer head in the other direction, a nozzle at the lower end of said frame adapted to hold in operative position the shank of a tool bit slidably fastened thereim'substantially as described.

In testimony whereof I have hereunto set my signature in the presence of two witnesses.

JOHN nonna'rs. -Witnesses:

ALEX. G. SOHU'MAN, Gno. E. SOHUMAN. 

